Credit: The Associated Press

FILE - In this April 23, 2013 file photo, family members of 18-year-old Abdella Ahmad Tounisi, including his father Ahmad Tounisi, center, leave the federal building in Chicago after the Chicago-area teen, charged with trying to join an al-Qaida-affiliated group in Syria appeared for a hearing. Abdella Ahmad Tounisi is expected to plead not guilty during his scheduled arraignment Wednesday, May 29, 2013, in Chicago.

CHICAGO — A suburban Chicago teenager has pleaded not guilty to charges he sought to join an al-Qaida-linked militant group fighting Bashar Assad's regime in Syria.

Abdella Ahmad Tounisi's attorney entered the plea Wednesday at a federal court in Chicago. The 18-year-old Tounisi stood by her side in orange jail garb, his legs shackled.

Authorities arrested Tounisi in April at O'Hare International Airport as he allegedly prepared for the first leg of a trip to join Jabhat al-Nusrah.